Electric clock



March 29, 1949. FINK I I 2,465,582

ELECTRIC CLOCK Filed Dec. 15, 1944 INVENTOR.

JEAN FlNK By I ATTY.

Patented Mar. 29, 1949 ELECTRIC CL'OCK' Jean Fink; Delavan; Wis., assignorto'lhe George W. Borg Corporation, Chicago, 111., a corporation of Delaware Application'December 13, 1944; Serial No. 568.009

5 Claims. 1

The" present invention relates to spring driven clocks, such as are used in automobiles; for ex-- ample; which are provided-with automatic elect-romagnetically operated winding mechanisms, ari'd 'the objectofthe invention is to provide a new'and improved switch-for controlling the winding mechanism in a clock of this character.

An automobile clock of the type with which the invention is concerned is shown in the patent toHobbs; No. 2-',146;119, granted February 7, 1939. The Hobbs clock has a switch which is closed with a snap action by means of a toggle device, said" device including a spring tensioned by the main spring of the clock and supplying the power toclose-the switch. Since the toggle spring is tensioned just prior to rewinding, the power which is required to tension it is taken from the main spring at a time when the latter is nearly run down and has little tension remaining beyond what is required to drivethe clock. In consequence of this somewhat inefiicient mechanical arrangement, the toggle spring has to be made rather weak, resulting in low contact pressure at the-switch, or the main spring has to be made stiffer-than would otherwise be necessary, which requires a more powerful electromagnet.

In contrast'to this known arrangement, my improved switch hasno toggle device, although it closes-with a-snap'action, and is not operated by power taken from the main spring. It is operatedby a spring which is'tensioned by the electromagnet during the winding operation and at a time when the magnet has surplus power beyond W-h'atis needed to tension the main spring. The newswitchis' superior from a mechanical standpoint, therefore; and makes it possible to secure increased contact pressure without increasing the size of 'an'y other'parts;

The'invention will be described more in detail hereinafter with reference" to the accompanying drawing, in which'- Fig lisa-transverse section through a clock embodying the invention showing the switch in open position ;v

Fig. 2 is a planview of theswitch on a larger scale in whichthe switch is shown in closed positioniand Fig. 3'shows the switchin' elevation; on the same scale as itis-shown in Fig; 2.

Referring to thedrawin g, the frame of the clock comprises a back plate ID, a center plate H, and a' front plate (not shown) which are secureditogetherin spaced relation'byimeans'of the usual pillars or posts. There. is also a bridge xlnlember. l:2 which is: attacheditothecenter plate Thereference character indicates-the center shaftor: minutesshaft ofthe clock, which. has hearings; in the bridge: member [2 and in the front plate. This? shaft:carries-the:minute hand 2 of the clock-and drives the hour hand in the usual manner;-

Thearmature- I? and the gear wheel it are retatably mounted on the center shaft [3 between the 'bridg'e' member IZ and the center plate ll. Thearmature-is rotated in a clockwise direction by the main spring 25, which is tensioned between the armature and an extension of the bridge member l2, and drives the gear wheel l5 by means of the pawl I8. A pawl l2 pivotally mounted on the lower side of the center plate H prevents retrograde movement of the gear wheel during winding or tensioning of the main spring. The winding operation is performed by an electromagnetZl mounted on the back plate It. The energization of the electromagnet rotates the armature i'! in a counter-clockwise direction, there by tensioning the main spring 20. In Fig. 1 the clock is shown in approximately fully wound condition.

The hub I4 is also rotatably mounted on the center shaft [3 and carries a cup-shaped spring housing l6 theopen end of which is closed by the gear l5; A spring located in the housing I6 connects the gear wheel I5 with the hub I4 and, with the pawl 19, constitutes the means for maintaining' power during winding. The clock train, escapement, andbalance are not shown but it will be understood thatthese parts are mounted betwee n the'cente'r plate H and the front plate in the usual manner. The first wheel of the clock train is'mounted on the hub It. The center shaft l3 is driven by means of a frictional connection (not shown) with the hub Hi.

The foregoing'brief description deals with parts notdirectly concerned with the invention and will he sufiicient-for a general understanding of the constructionandoperation of the clock. For further details reference may be had to the Hobbs patent.

The circuit ofthe'electromagnet 2! is com trolled by a switch which will now be described morein detail.

The switch includes a relatively-fixed contact member 25 and azmovable contact member 26. The fixed' contact member 25 is mounted on the insulator 2'! by means of the rivet 28 and the insulator: is secured to the backplate H! by the rivet 29. The movable contact member 26 is pivotedt on the post 30 by means of the shoulder screw 3|; A spring. 32 surrounding post 3i! and tensioned between the stud 33 on back plate It! and stud 34 on'contact member 26, tends to rotate the contactmember 26 in a clockwise directionas'seen in Figsrl and 2 to close the switch.

Thareference character 35 indicates a quick releasemember which is pivoted on the contact member'ZG. by meansof the shoulder: screw 35. The member 35 has anintegl'ally formed stop 38. Theli'spring 131 is? supported-on stud- 34 and tends to rotate the release member 35 in a counterclockwise direction as seen in Figs. 1 and 2, such rotation being limited by the engagement of stop 38 with the edge of the contact member 26.

The switch is operated and controlled by a roller 40 mounted on a stud 4| fixed to the armature IT. The roller cooperates with the cam surfaces 42 and 43 of the contact member 26 and with the release member 35 in a manner to be presently explained.

t will be understood that the switch is connected in series with the electromagnet 2|. The ungrounded pole of the battery is connected to one end of the winding of the electromagnet by means of a suitable terminal on the back plate It. The other end of the winding is connected to the insulated fixed contact member by means of the conductor 44, Fig. 1. When the switch is closed the circuit is completed to the grounded pole of the battery by the contact member 26, the frame of the clock and the frame of the car.

The operation of the clock and more especially the operation of the winding mechanism and the switch, will now be explained.

For this purpose it may be assumed that the main spring 20 is substantially fully wound as shown in Fig. 1. The switch is open, the contact member 26 being held in the position in which it is shown by the engagement of roller 40 with the cam surface 43. Spring 32 iS under considerable tension and tends to close the switch.

The main spring slowly rotates the armature I! in a clockwise direction and the armature rotates the gear I5 by means of pawl l8. Gear l5 drives hub l4, and the hub l4 drives the clock train, the first wheel thereof being mounted on the hub. The hub also drives the center shaft l3 through its frictional connection thereto. The clock thus runs by power supplied by the main spring.

As the armature I1 is rotated by the main spring, the roller 40 rides on the cam surface 43, which in the open position of the switch is concentric with shaft l3, or the rotation axis of the armature. The contact member 26 accordingly remains stationary in open position. When the roller reaches the end of cam surface 43 it does not ride down on cam surface 42 but rides along the cam surface 45 on the release member 35, the cam surface 45 acting as an extension or prolongation of cam surface 43. Since the cam surface 4-5 is past dead center, the release member 35 has a tendency to rotate on its pivot 36 in a counterclockwise direction, which it cannot do,

however, because of the engagement of the stop 38 with the edge of the contact member 28. The contact member is accordingly maintained in open position.

Before the power in the main spring becomes too far exhausted the roller reaches the end of cam surface and the switch is closed. The switch closes with a snap action due to the fact that as soon as the center of the roller 40 gets a little past the end of cam surface 45 the release member 35 suddenly starts to rotate on its pivot in a clockwise direction, thereby releasing the contact member 26 and allowing it to be moved quickly to closed position by the spring 32. The release member 35 rotates against the tension of spring 31 because of the force applied by spring 32, which develops an increasing component acting to rotate member 35 when the roller 45 reaches the position stated.

The closure of the switch completes the circuit of the electro-magnet 2|, which thereupon energizes and quickly rotates the armature l1 substantially to the position in which it is shown in Fig. 1, thereby winding or retensioning the main spring 20. At the beginning of this rotation of the armature I! the roller 40, which has slipped off the cam surface 45 on release member 35, simply rotates the release member in a clockwise direction and the closed position of contact member 26 is not disturbed. As the rotation of the armature continues, however, the roller 40 engages the cam surface 42 and rotates the contact member 26 to open the switch. At this time the release member 35 is restored by the light spring 31. The switch is opened at about the mid-point in the travel of the armature, at a time when the attraction between the electromagnet and thearmature is substantially a maximum and the main spring 20 is only partly wound. There is ample power available therefore for the tensioning of spring 32 which results from the opening of the switch. The armature continues to rotate after the switch has been opened, due partly to the inertia of the armature and partly to the effect of the spark quenching condenser (not shown) until the rotation is stopped by the increasing tension in the main spring.

During the rotation of the armature IT by the eiectromagnet 2| the gear I5 is prevented from rotating backward by pawl 19 and the clock train is driven by the power maintaining spring. As soon as the rotation ceases the pawl l8 takes a fresh hold on gear l5 and the drive from power supplied by the main spring is resumed, the power maintaining spring being retensioned at this time.

t will be noted that during the rotation of the armature by the main spring the roller 40 merely holds the switch open, by reason of its engagement with cam surfaces 43 and 45. The contact member 26 remains stationary and no power is taken from the main spring by the switch except the minute and negligible amount required to overcome the friction of the roller. Substantially all the power stored in the main spring is therefore available for driving the clock.

It may be pointed out that in the normal operation of the clock the roller 40 never quite reaches the position in which it is shown in Fig. 2. The switch is closed responsive to rotation of the release member 35, which will evidently take place when the roller is still some little distance to the right.

In case the closure of the switch does not re suit in the energization of the electromagnet, as may happen sometimes due to a dirty contact, the rotation of the armature in a clockwise direction continues after the switch has closed until the roller 40 reaches its Fig. 2 position, or a little beyond this position, when the armature engages the arm 53 of contact member 26. The mainspring 20 now aids the spring 32 in pressing the contact member 26 against the fixed contact member 25 and since the latter is somewhat flexible, it yields a trifle and a slight rubbing action ensues which is generally effective to close the circuit. It will be understood that switch failure because of a dirty contact is very rare, but if it should occur the full power remaining in the main spring is available to force the contacts together as described and thus clear the trouble and avoid stoppage of the clock.

' The invention having been described, that which is believed to be new and for which the protection of Letters Patent is desired will be pointed out in the appended claims.

I claim:

1. In a clock, a rotatable armature, an electromagnet for rotating said armature in one direction, a main spring tensioned by such rotation to drive the clock by rotating said armature in the opposite direction, a switch for cont-rolling the circuit of said electromagnet, means including said armature for closing the switch during rotation of the armature by said main spring and for opening the switch during rotation of the armature by the electromagnet, a spring tensioned each time the switch in opened to store power for closing it, and means effective in case the closure of said switch fails to energize said electromagnet for supplying .power from said main spring to increase the pressure on the switch contacts, said last means comprising a member forming part of said switch and located beyond the normal range of movement of said armature but arranged to be engaged by the armature in the event of extended movement thereof due to the failure of said electrio-magnet to energize.

2. In a clock, a main spring, an electromagnet, a rotatable armature rotated quickly in one direction by energization of said electromagnet to tension said main spring and rotated slowly in the opposite direction by said main spring to drive the clock, a switch controlling the circuit of said electromagnet, said switch including .a pivoted member having a cam surface, a spring acting on said pivoted member and tending to close the switch, an opera-ting member carried by said armature and engaging said cam surface during the quick rotation of the armature to rotate said pivoted member to open said switch, said operating member also engaging said cam surface during the slow rotation of said armature to hold the switch open, and means comprising a pivoted release member carried by said pivoted member providing a limited extension of said cam surface which is engaged by said operating member to delay the closing of said switch.

3. In a clock, a rotatable armature, an electromagnet for rotating said armature in one direction, a main spring tensioned by such rotation to drive the clock by rotating said armature in the opposite direction, a switch controlling the circuit of said electromagnet, said switch including a pivoted contact member, a spring continuously acting on said contact member to close the switch, an operating member carried by said armature and effective when the armature is rotated by said electromagnet to engage said contact member and rotate the same on its pivot against the tension of said spring to open the switch, and a member pivoted on said contact member and adapted to cooperate with said operating memher during the rotation of said armature by said main spring to maintain the contact member ace tuated and to release it at a predetermined point in the rotation of the armature to close said switch.

4. In a clock, a main spring, an electromagnet, a rotatable armature rotated in one direction by energization of said electromagnet to tension said main spring and rotated in the opposite direction by said main spring to drive the clock, a switch controlling the circuit of said electromagnet, said switch including a pivoted member having a cam surface, a spring acting on said pivoted member and tending to close the switch, an operating member carried by said armature and engaging said cam surface when the armature is rotated by said electromagnet to rotate said pivoted member to open said switch, and a quick release device carried by said pivoted member providing an extension of said cam surface which is engaged by said operating member when the armature is driving the clock to hold the said switch open, said release device being movable relative to said pivoted member when said operating member reaches the end of said extension to effect closure of said switch with a snap action.

5. In a clock, a main spring, an electromagnet, a rotatable armature rotated in one direction by energization of said electromagnet to tension said main spring and rotated in the opposite direction by said main spring to drive the clock, a switch controlling the circuit of said electromagnet, said switch including a .pivoted member having a cam surface, a spring acting on said pivoted member and tending to close the switch, a. quick release device pivoted on said pivoted member and having a cam surface adapted to function as a prolongation of said first mentioned cam surface, and an operating member carried by said armature and cooperating with said first mentioned cam surface when the armature is rotated by said electromagnet to open the switch, said operating member cooperating with both cam surfaces during the rotation of the armature by the main spring to hold the switch open for a predetermined time and acting to rotate said release device at the end of said time to release said pivoted member and thereby close the switch.

JEAN FINK.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,882,891 Porter Oct. 18, 1932 2,164,976 Whitehead July 4, 1939 2,214,654 Bates Sept. 10, 1940 

